The type and amount of matrix proteins synthesized by human tumor cells in vitro appears to parallel that of cultured normal cell counterparts to some extent. We wish to broaden these observations to a variety of human tumors, and determine whether differentiation in vitro induced by differentiating agents will cause a reversion to more normal patterns of collagen synthesis, and whether these patterns might allow more precise categorization of the tumor's origins. In addition, the analysis will include a search for any new or atypical matrix proteins unique to these tumors. Such proteins may be useful in studying extracellular matrix assembly and function.